"Nothing is left for the last minute," said Sir Malcolm Ross, who planned celebrations for the royal family (including Charles and Camilla's wedding) for almost two decades. "Absolutely nothing ... in the palace, in the Middleton household, everything will have been arranged, ordered and it will be available for the day."

Don't expect any surprises, Ross added.

"Nothing will go wrong," he said. "I mean there is no room for error."

In order for nothing to go wrong, everything -- quite literally -- has been thought of. Believe it or not, the cobblestones outside Westminster Abbey have been given special treatment.

"They have been vacuumed," Ross said. "We are aware that we're producing a show. And we must make it something that the world will enjoy and we will be proud of."

The view from behind the scenes is distinctly different from what the public sees, and something that is rarely talked about.

ABC's Barbara Walters recently spoke exclusively with India Hicks, who was 13 in 1981 when her godfather, Prince Charles, asked her to be his bridesmaid.

"She turned up in a pair of jeans," Hicks said. "I have this lasting impression of Diana with a diamond tiara on top of her head, dressed in jeans below while they fitted the tiara to see what it would look like."

Princess Diana's Pre-Wedding Routine

And it turns out Diana was watching the television as she got dressed.

"She was very intrigued by it," Hicks said. "For her, it was so new to see herself on television. Can you imagine? I mean her whole life going before her eyes and she kept pushing everybody out of the way; move, she'd say."

The little bridesmaid had one simlple thought when she saw Diana in that dress.

"I thought, a princess. She was the bride; all brides have that sense of being the center of attention," Hicks said. "But she had that star quality."

Hicks kept a scrapbook of Charles and Diana's wedding day, along with a program just given to wedding participants.

"With the train and all crumpled; a big crumpled mess comes out of the carriage," Hicks said.

India and Sarah had the job of managing that famous train, that stretched a record-breaking 25 feet.

"The job wasn't going right," Hicks said.

But Diana was sympathetic, "and turned round and just said, 'Do your best.'"

And so India navigated her way up the aisle in front of a global audience of 750 million people.
"I was thinking my shoes hurt, they're pinching," Hicks said, "and it was a long way down that red carpet to the altar. But there was an aura about that day."

When the time came for the official photographs, it seemed they would never end.
"We had to keep smiling and smiling and smiling. Prince Andrew began to tell terrible jokes. And I think by the end, we were laughing and exhausted," Hicks said.

"And Diana slumped down onto the floor and we all just collapsed on the floor."

Palace Officials Quick on Their Feet

Hicks comes from a family of royal bridesmaids. Her mother, Lady Pamela Mountbatten, was an 18-year-old bridesmaid to her cousin, Lt. Philip Mountbatten in 1947, when he married none other than Elizabeth, who was to become queen.

The morning of this wedding was marked with yet another wardrobe malfunction.

"Queen Mary, her grandmother, had given her [Elizabeth] a magnificent diamond tiara," Lady Pamela recalled. "So they have it poised over her head, about to place it on her head; it breaks in two."

"But, luckily, of course, Buckingham Palace is the one place in the world where if you break your tiara, you can say, 'Do fetch me another diamond tiara.'"

"So, in fact, her mother produced another lovely tiara," Lady Pamela said.

Now, it seems that despite Ross' words, there have indeed been royal blips in the past. But Middleton and Will need not worry. If history is anything to go by, the royal family are pros at seemlessly implementing a back-up plan.